The deal is for $3 million, according to a source familiar with the situation.
It includes a $4 million option for 2021 or a $250,000 buyout, a source said.
Kintzler, 35, is coming off one of the best seasons of his career, having compiled a 2.68 ERA and 1.018 WHIP with the Chicago Cubs. The former All-Star closer with the Minnesota Twins could regain his ninth-inning role with the Marlins, who have a young team.
Kintzler could also thrive in the three-batter-minimum era, given that he held lefties to a .163 batting average last season. He's a former 40th-round draft pick of the New York Yankees, and he has played 10 seasons. The Marlins will be Kintzler's fifth team.
The contract increases to a $500,000 buyout if he is traded this year or a $5 million option for 2021.